Low profile lamp using tir lens

ABSTRACT

A lamp is provided which is suitable for use in low-profile applications. The lamp includes a light source and a lens. The lens includes a first surface opposite a second surface, where the second surface includes an injection surface and the first surface includes a multi-faceted optical element converging towards the injection surface. The light source injects light into the lens via the injection surface and the light refracts through the first surface while total internally reflecting off the first surface and the second surface toward the periphery of the lens.

BACKGROUND

The present exemplary embodiments relate generally to lighting. Theyfind particular application in conjunction with low profile lamps, andwill be described with particular reference thereto. However, it is tobe appreciated that the present exemplary embodiments are also amenableto other like applications.

A lamp generally includes one or more light sources which may degradeover time and/or with temperature. However, lamps often lack the abilityto compensate for and/or provide notice of such degradation. As aresult, a lamp may not operate according to specification and/or providean operator of the lamp with sufficient notice to replace the lampbefore failure.

Further, a lamp generally includes a light emitting face through whichlight from the one or more light sources is emitted. Typically, it ispreferable that light be uniformly emitted from the light emitting face.However, a light emitting face of a lamp is often larger than the lightsource. As such, uniform distribution of light emitted from the lightsource can be difficult to achieve.

One option includes the use of a catadioptric optical system. Acatadioptric optical system uses refraction and reflection, usually vialenses (dioptrics) and curved mirrors (catoptrics), to focus light.However, one problem with using a catadioptric optical system is thatcatadioptric optical systems are generally fairly thick. Therefore, ininstances where a low profile lamp is required, it is often difficult tomake use of a catadioptric optical system.

Another option involves using a matrix of light sources spread along thelight emitting face of a lamp. Such an option does not rely on anoptical system to distribute light from a light source across a lightemitting face of a lamp. Rather, it relies on sheer quantity of lightsources. However, one problem with using a matrix is that increasing thequantity of light sources adds unnecessary expense, inefficiency, andcomplexity to a lamp.

The present disclosure contemplates new and improved systems and/ormethods for remedying this and other problems.

BRIEF DESCRIPTION

Various details of the present disclosure are hereinafter summarized toprovide a basic understanding. This summary is not an extensive overviewof the disclosure and is intended neither to identify certain elementsof the disclosure, nor to delineate the scope thereof. Rather, theprimary purpose of the summary is to present certain concepts of thedisclosure in a simplified form prior to the more detailed descriptionthat is presented hereinafter.

According to one aspect of the present disclosure, a lamp is provided.The lamp includes a light source and a lens. The lens includes a firstsurface opposite a second surface, where the second surface includes aninjection surface and the first surface includes a multi-faceted opticalelement converging towards the injection surface. The light sourceinjects light into the lens via the injection surface. This lightrefracts through the first surface while total internally reflecting offthe first surface and the second surface toward the periphery of thelens.

According to another aspect of the present disclosure, a lamp isprovided. The lamp includes a light source, a light sensor, and a powersupply. The power supply controls light output of the light source basedon measured light output from the light sensor. The lamp furtherincludes a lens, where the lens includes a light emitting face. The lensis configured to receive light emitted from the light source anduniformly distribute the received light across the light emitting faceusing total internal reflection and refraction. The light sensor isdisposed on the light emitting face of the lens.

According to another aspect of the present disclosure, a lens isprovided. The lens includes a first surface opposite a second surface,where these surfaces define a waveguide channel. Light directed to thefirst surface and/or the second surface total internally reflects to aperiphery of the lens. The lens further includes an injection surfacereceiving light from a light source and a multi-faceted optical elementopposite the injection surface. The multi-faceted optical elementconverges toward the injection surface, where light received by theinjection surface total internally reflects off the multi-facetedoptical element to the periphery of the lens.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and drawings set forth certain illustrativeimplementations of the disclosure in detail, which are indicative ofseveral exemplary ways in which the various principles of the disclosuremay be carried out. The illustrative examples, however, are notexhaustive of the many possible embodiments of the disclosure. Otherobjects, advantages and novel features of the disclosure will be setforth in the following detailed description of the disclosure whenconsidered in conjunction with the drawings, in which:

FIG. 1 is a block diagram of a lamp according to aspects of the presentdisclosure;

FIG. 2 is a top plane view of a lamp according to aspects of the presentdisclosure;

FIG. 3 is cross sectional view of the lamp of FIG. 2;

FIG. 4 is a top plane view of a revolved lens according to aspects ofthe present disclosure;

FIG. 5 is a cross sectional view of the lens of FIG. 4; and,

FIG. 6 is an extruded lens according to aspects of the presentdisclosure.

DETAILED DESCRIPTION

One or more embodiments or implementations are hereinafter described inconjunction with the drawings, where like reference numerals are used torefer to like elements throughout, and where the various features arenot necessarily drawn to scale.

With reference to FIG. 1, a block diagram of a lamp 100 according toaspects of the present disclosure is provided. The lamp 100 may, forexample, be a traffic lamp, a lamp employed by the backlight of certainwatches, and the like. The lamp 100 may include one or more of a lightsource 102, a lens 104, one or more sensors 106, a power supply 108, amemory 110, a communications unit 112, a controller 114, and the like.

The light source 102 suitably generates light for the lamp 100. Thelight source 102 may include one or more types such as guided light(e.g., light guided from optical fibers or other types of light guides);direct electric-powered light emitters (single or cluster), such aselectroluminescent sources (LEDs, organic LEDs, polymer LEDS, etc.), gasdischarge sources (fluorescent, plasma, etc.), high-intensity dischargesources, lasers, non-linear light sources; and the like. The lightsource 102 may be selected to control Correlated Color Temperature(CCT), Color Rendering Index (CRI), and other like characteristics oflight.

The lens 104 suitably distributes light from the light source 102uniformly across a light emitting face of the lamp 100. As discussed ingreater detail below, this may be achieved using a positive lens thatworks partially on refraction and partially on total internalreflection. In certain embodiments, the lens 100 may occupy at leasthalf the light emitting face and/or the light source 102 may bepositioned away from the lens 104 less than ¼ of the radius or focallength of the lens 102. Further, in certain embodiments, the lens may betreated to increase uniformity, improve lit appearance, and/or reduceglare. Additionally or alternatively, another optical component, such asa diffusing film, may be used to achieve a similar affect.

The sensors 106 suitably measure one or more operating conditions of thelamp 100. Operating conditions may include one or more of input voltage,operating temperature, output current and/or voltage to the light source102, light output of the light source 102, and the like. In certainembodiments, the sensors 106 may include a photo-electric transducer,such as a solid-state photo-detector. In such embodiments, thephotoelectric transducer can be connected to any surface of the lens104. However, a surface with less impact on the optical performance ofthe lens 104, typically an outer surface, is preferable. In certainembodiments, the sensors 106 may additionally or alternatively include athermistor.

The power supply 108 suitably receives power from an external powersource (not shown) and distributes the power to the constituentcomponents of the lamp 100. The input voltage of the received power maybe an alternating current (AC) voltage or a direct current (DC) voltage.In certain embodiments, the power supply 108 may receive commands fromthe controller 114 and/or an external device (not shown), controllingthe distribution of the power. For example, the power supply 108 mayreceive commands from the controller 114 instructing the power supply108 as to the output current and/or voltage to provide to the lightsource 102. In other embodiments, the power supply 108 may receive asignal from the sensors 106, such as the photo-electric transducer, andadjust the output current and/or voltage to the light source 102 tomaintain a constant light output.

The power supply 108 suitably includes one or more hardware componentsfor distribution of the power to the lamp 100. For example, the powersupply 108 may include one or more of a rectifier, surge protectioncircuit, an electromagnetic interference circuit, a switching powersupply, a conflict monitor, a fuse, a fuse blowout (FBO) circuit, apower factor correcting power supply, and the like. However, othercomponents, such as software components, are equally amenable.

The memory 110 suitably stores log data associated with one or moreoperating conditions in a stateful manner. For example, the memory 110may store the operating time of the traffic lamp 100. The memory 110 mayinclude one or more of a magnetic disk or other magnetic storage medium;an optical disk or other optical storage medium; a random access memory(RAM), read-only memory (ROM), or other electronic memory device or chipor set of operatively interconnected chips; and the like.

The communications unit 112 suitably provides the controller 114 with aninterface from which to communicate with other lamps and/or componentsexternal to the lamp 100. For example, the communications unit 112 mayallow the lamp 100 to receive commands from an external controller (notshown). The communications unit 112 may communicate with these otherlamps and/or components external to the lamp 100 via, for example, acommunications network, such as a local area network, wide area network,the Internet, and so on, and/or a data bus, such as I2C, universalserial bus, serial, and so on.

The controller 114 suitably monitors operating conditions of the lamp100. Monitoring may include receiving data pertaining to one or moreoperating conditions of the lamp 100 from one or more hardware and/orsoftware components comprising the lamp 100, such as the sensors 106.The received data may include the present values of operating conditionsand/or data necessary to calculate the present values of operatingconditions. Monitoring may further include calculating values for one ormore operating conditions from the received data and/or determiningwhether the operating conditions are within acceptable limits based onthis received data. As to the determination, values for operatingconditions (whether calculated or directly measured) may be comparedagainst thresholds and/or expected values for the operating conditions.If an operating condition falls outside acceptable limits a fault isdetected.

In certain embodiments, the controller 114 may instruct the power supply108 as to the output current and/or voltage to provide to the lightsource 102, so as to account for degradation factors, while monitoringoperating conditions of the lamp 100. Degradation factors reduce thelight output of the light source 102 and may include one or more ofoperating time of the light source 102, operating temperature of thelamp 100, and the like. The controller 114 may adjust the power supplyoutput current and/or voltage on the basis of light output of the lightsource 102 as determined by one of the sensors 106, such as thephoto-electric transducer. Alternatively, the controller 114 may adjustthe power supply output current and/or voltage on the basis of acalculated output current and/or voltage.

A calculated power supply output I_(out) may be defined as:

I _(out) =I _(nom) *f _(TH) *f _(De),  (1)

where I_(nom) is the nominal output current to the light source 102,f_(TH) is a correction factor adjusting for temperature inside the lamp100, and f_(De) is a correction factor adjusting for the age of thelight source 102. The correction factors may be determined through theuse of one or more lookup tables in which correction factors are indexedby present values of operating conditions. A calculated output voltageV_(out) can similarly be calculated.

In certain embodiments, the controller 114 may log operating conditionsof the lamp 100 while monitoring operating conditions of the lamp 100.The process of \ogging operating conditions of the lamp 100 may includewriting values (calculated or otherwise) of one or more of the operatingconditions to the memory 110. The values of operating conditions mayoverwrite previously written log data and/or be written as a log entryindexed by time. Logging may be performed when one or more of theoperating conditions are determined to fall outside acceptable limits(i.e., a fault is detected). However, other triggers for logging areequally amenable. For example, logging may be performed at periodicintervals as determined by, for example, a timer of the lamp 100. Asanother example, logging may be performed right before the lamp 100 goesinto an OFF state.

In certain embodiments, the controller 114 may generate an indication ifa fault is detected while monitoring operating conditions of the lamp100. For example, if the operating temperature and/or operating time ofthe lamp 100 exceed certain thresholds the controller 114 may generatean indication. The indication may include generating an indicationsignal. The indication signal may be provided to a local component ofthe lamp 100 and/or an external component thereof. Further, theindication signal may be used for one or more of generating an audioand/or visual warning, flashing one or more light sources, enabling afault light source, and the like.

The controller 114 may include a digital/electronic processor, such as amicroprocessor, microcontroller, graphic processing unit (GPU), and thelike. In such embodiments, the controller 114 suitably executesinstructions stored on a memory. In certain embodiments, the memory maybe the memory 110 of the lamp 100. In other embodiments, the memory maybe local to the controller 114 and one of ROM, EPROM, EEPROM, Flashmemory, and the like. The controller 114 may communicate with the memory110 of the lamp 100 via a digital communications protocol, such as I2C,USB, RS-232, RS-485, 1 Wire, SPI, WiFi, and the like. However, analogcommunications protocols are equally amenable. The communicationsprotocol may be carried over one or more of a data bus, a communicationsnetwork, and the like.

With reference to FIGS. 2 and 3, a lamp 200 according to aspects of thepresent disclosure is provided. FIG. 2 provides a top plane view of thelamp 200 and FIG. 3 provides a cross sectional view of the lamp 200along line 202. The lamp 200 is a more specific embodiment of the lamp100 of FIG. 1. Therefore, the discussion heretofore is equally amenableto the discussion to follow and components described hereafter are to beunderstood as paralleling like components discussed heretofore, unlessnoted otherwise. The lamp 200 may include one or more of a housing 204,a memory 206, a light source 208, a light emitting face 210, a lens (notshown), one or more sensors 212, a power supply 214, a communicationsunit 216, a controller 218, a circuit board 220, and the like.

The housing 204 suitably defines the body of the lamp 200. The housing204 may provide a mounting structure and/or protection for components ofthe lamp 200. Further, the housing 204 may be formed from one or more ofa polymeric material, a metallic material, and the like. In certainembodiments, the housing 204 may act as a heat sink to draw heat awayfrom the components of the lamp 200.

The memory 206 suitably stores log data associated with one or moreoperating conditions in a stateful manner. For example, the memory 206may store the operating time of the traffic lamp 200. The memory 206 mayinclude one or more of a magnetic disk or other magnetic storage medium;an optical disk or other optical storage medium; a random access memory(RAM), read-only memory (ROM), or other electronic memory device or chipor set of operatively interconnected chips; and the like.

The light source 208 suitably generates light for the lamp 200. Thelight source 208 may include one or more of guided light, such as lightguided from optical fibers or other types of light guides; directelectric-powered light emitters (single or cluster), such aselectroluminescent sources (LEDs, organic LEDs, polymer LEDS, etc.), gasdischarge sources (fluorescent, plasma, etc.), high-intensity dischargesources, lasers, non-linear light sources, and the like. The lightsource 208 may be selected to control Correlated Color Temperature(CCT), Color Rendering Index (CRI), and other like characteristics oflight.

The light emitting face 210 suitably corresponds to the portion of thelamp 200 out of which light from the light source 208 is emitted. Putanother way, the light emitting face 210 may be viewed as the boundarythrough which light from the light source 208 passes to get to theexternal environment of the lamp 200. In certain embodiments, the lightemitting face 210 and the light emitting face of the lens may be one andthe same.

The lens suitably uniformly distributes light from the light source 208across the light emitting face 210 of the lamp 200. As discussed indetail below, this may be achieved using a positive lens that workspartially on refraction and partially on total internal reflection. Incertain embodiments, the lens may occupy at least half the lightemitting face 210 and/or the light source 208 may be positioned awayfrom the lens less than ¼ of the radius of the lens. Further, in certainembodiments, the lens may be treated to at least one of increaseuniformity, improve lit appearance, and reduce glare. Additionally oralternatively, another optical component, such as a diffusing film, maybe used to achieve a similar affect.

The sensors 212 suitably measure one or more operating conditions of thelamp 200. Operating conditions may include one or more of input voltage,operating temperature, output current to the light source 208, lightoutput of the light source 208, and the like. The sensors 212 mayinclude, for example, one or more of a photo-electric transducer (notshown), such as a solid-state photo-detector, a thermal-electrictransducer (shown), such as a thermistor, and the like. In certainembodiments, the photo-electric transducer is disposed on the lightemitting face of the lens.

The power supply 214 suitably receives power from an external powersource (not shown) and distributes the power to the constituentcomponents of the lamp 200. In certain embodiments, the power supply 214may receive commands from the controller 216 and/or an external device(not shown), controlling the distribution of the power. For example, thepower supply 214 may receive commands from the controller 216instructing the power supply 214 as to the output current to provide tothe light source 208.

The communications unit 216 suitably provides the controller 218 with aninterface from which to communicate with other lamps and/or componentsexternals to the lamp 200. The communications unit 216 may communicatewith these other lamps and/or components external to the lamp 200 via,for example, a communications network, such as a local area network,wide area network, the Internet, and so on, and/or a data bus, such asI2C, universal serial bus, serial, and so on.

The controller 218 suitably monitors operating conditions of the lamp200. In certain embodiments, the controller 218 may instruct the powersupply 214 as to the output current to provide to the light source 208,so as to account for degradation factors, while monitoring operatingconditions of the lamp 200. Degradation factors reduce the light outputof the light source 208 and may include one or more of operating time ofthe light source 208, operating temperature of the lamp 200, and thelike. In other embodiments, the controller 218 may additionally oralternatively log operating conditions, such as operating time, of thelamp 200 to the memory 206 while monitoring operating conditions of thelamp 200. In other embodiments, the controller 218 may additionally oralternatively generate an indication if a fault is detected whilemonitoring operating conditions of the lamp 200. The indication mayinclude generating an indication signal, which may be used to generatean audio and/or visual notification.

The circuit board 220 suitably provides a mounting point for one or moreof the controller 218, the communications unit 216, the power supply214, the light source 208, the memory 206, one or more of the sensors212, and the like. Further, the circuit board 220 suitably interconnectsthe components electrically. In certain embodiments, the circuit board220 may act as a heat sink for components mounted thereon and/or includea metal core printed circuit board. The circuit board 220 may mount tothe housing 204 of the lamp 200 by, for example, mechanical fasteners,glue, tape, epoxy, and the like.

With reference to FIGS. 4 and 5, a revolved lens 400 according toaspects of the present disclosure is provided. FIG. 4 provides a topplane view of the lens 400, and FIG. 5 provides a cross sectional viewof the lens 400 along line 402. The lens 400 is suitably employed withina lamp, such as the lamp 100 of FIG. 1 and/or the lamp 200 of FIGS. 2and 3.

The lens 400 may include one or more of a first surface 404, a secondsurface 406, a waveguide channel 408, a multi-faceted optical element410, an injection surface 412, and the like. As the lens 400 is orientedin FIG. 5, the first surface 404 may be viewed as the top surface of thelens 400, and the second surface 406 may be viewed as the bottom surfaceof the lens 400. Further, it is to be appreciated that the first surface404 and the second surface 406 need not be continuous. For example, asshown, the first surface 404 includes the multi-faceted optical element410 and the second surface includes the injection surface 412.

The first surface 404 and the second surface 406 suitably interact todefine the waveguide channel 408, which may distribute light to theperiphery 414 of the lens 400 using total internal reflection. Lightsuitably refracts through the first surface 404 as it travels to theperiphery 414 of the lens 400 via the waveguide channel 408. In certainembodiments, the light may travel along a line greater than a criticalangle for total internal reflection with respect to the first surface404 and/or the second surface 406. Further, in certain embodiments, theouter edges of the first surface and the second surface may becoincident.

Light directed towards the first surface 404 suitably partially reflectsoff the first surface 404 towards the second surface 406. Reflectionsuitably employs both total internal reflection and simple reflection.Further, light directed towards the first surface 404 suitably partiallyrefracts through the first surface 404. In that regard, it is to beappreciated that the first surface 404 defines the light emitting faceof the lens 400. In certain embodiments, the first surface 404 mayinclude a diffusing treatment to increase uniformity.

Light directed towards the second surface 406 suitably reflects off thesecond surface 406 towards the first surface 404. Reflection suitablyemploys both total internal reflection and simple reflection. So as tofacilitate reflection, the second surface 406 suitably includes aplurality of converging facets, such as a first facet 416. Suitably, theconverging facets, in conjunction with the multi-faceted optical element410, are configured to simulate a focal point 417 different than that ofthe position of the light source. The converging facets may include aplurality of optical surfaces, such as optical surfaces 418, and aplurality of non-optical surfaces, such as non-optical surfaces 420. Theoptical surfaces, in contrast with the non-optical surfaces, mayredirect light directed thereto to the first surface 404, typically viatotal internal reflection.

The multi-faceted optical element 410 suitably reflects and refractslight directed thereto. Reflection includes total internal reflectionand/or simple reflection. For example, the multi-faceted optical element410 may total internally reflect a portion of light directed thereto tothe second surface 406 and/or the first surface 404 and refract theremainder of light directed thereto away from the lens 400. To do so,the multi-faceted optical element 410 suitably includes a plurality ofcusps formed from a plurality of optical surfaces, such as opticalsurfaces 424, and a plurality of non-optical surfaces, such asnon-optical surfaces 422. Light directed to the multi-faceted opticalelement 410 typically refracts through the non-optical surfaces, andreflects, typically using total internal reflection, off the opticalsurfaces towards the second surface 406.

The multi-faceted optical element 410 may converge towards the secondsurface 406 and/or be configured in a Fresnel way. The multi-facetedoptical element 410 may, but need not, be centrally located within thelens 400 and/or aligned with the center of a light source used inconjunction with the lens 400. Putting the latter another way, the pointof convergence 426 of the multi-faceted optical element 410 may bealigned with the center of the light source. Suitably, the facets areconfigured to simulate the focal point 417 different than that of theposition of the light source.

The injection surface 412 suitably acts as the receiving area of thelens 400 for light emitted by a light source used in conjunction withthe lens 400. The injection surface 412 may receive light emitted by alight source 428 placed within 25% of the simulated focal distance ofthe lens 400 for the simulated focal point 417. Further, the injectionsurface 412 may include a spherical surface, where a light source ispositioned in the center thereof. In certain embodiments, the injectionsurface 412 may include no optical power.

With reference to FIG. 6, a perspective view of an extruded lens 600according to aspects of the present disclosure is provided. The lens 600is suitably employed within a lamp, such as the lamp 100 of FIG. 1. Aswith the lens 400 of FIGS. 4 and 5, the lens 600 makes use of acombination of total internal reflection and refraction to uniformlydistribute light from a light source across a light emitting face.Further, the cross section of the extruded lens 600 is the same as thecross sectional view of the lens 400 of FIG. 5, whereby it is to beappreciated that the lens 600 operates as described in connection withthe lens 400 of FIGS. 4 and 5. Therefore, in lieu of repeating thediscussion of the lens 400 of FIGS. 4 and 5, attention is directed tothe discussion of the lens 400 of FIGS. 4 and 5 above.

The disclosure has been made with reference to preferred embodiments.Obviously, modifications and alterations will occur to others uponreading and understanding the preceding detailed description. It isintended that the preferred embodiments be construed as including allsuch modifications and alterations insofar as they come within the scopeof the appended claims or the equivalents thereof.

1. A lamp comprising: a light source; and a lens including a firstsurface opposite a second surface, said second surface including aninjection surface and said first surface including a multi-facetedoptical element converging towards the injection surface, wherein saidlight source injects light into the lens via the injection surface,wherein said injected light refracts through the first surface whiletotal internally reflecting off the first surface and the second surfacetoward the periphery of the lens.
 2. The lamp of claim 1, wherein thefirst surface includes a diffusing treatment.
 3. The lamp of claim 1,wherein the first surface and the second surface are coincident at theperiphery of the lens.
 4. The lamp of claim 1, wherein the secondsurface includes a plurality of converging facets facilitating totalinternal reflection of light toward the periphery of the lens.
 5. Thelamp of claim 4, wherein the converging facets simulate a focal pointfarther from the lens than the light source.
 6. The lamp of claim 1,wherein the multi-faceted optical element is aligned with a center ofthe light source.
 7. The lamp of claim 1, further comprising: a lightingemitting surface, wherein said lens occupies a majority of the lightingemitting surface.
 8. The lamp of claim 1, wherein the light source ispositioned a distance less than ¼ of a simulated focal length of thelens.
 9. The lamp of claim 1, wherein the lens is generated by extrusionand/or revolving.
 10. The lamp of claim 1, wherein the injected lighttravels to a periphery of the lens along a line greater than a criticalangle for total internal reflection with respect to said first surfaceand/or said second surface.
 11. A lamp comprising: a light source and alight sensor; a power supply controlling light output of the lightsource based on measured light output from the light sensor; and a lensincluding a light emitting face, said lens configured to receive lightemitted from the light source and uniformly distribute said receivedlight across the light emitting face using total internal reflection andrefraction, wherein said light sensor is disposed on the light emittingface of the lens.
 12. The lamp of claim 11, wherein the light sensor isa photo-electric transducer.
 13. The lamp of claim 11, furthercomprising: a controller monitoring light output of the light sourceusing the light sensor and correcting for degradation in light output ofthe light source using the light sensor.
 14. The lamp of claim 13,wherein the controller corrects for degradation in light output of thelight source by instructing the power supply as to output current toprovide to the light source
 15. The lamp of claim 11, wherein the lensincludes a first surface and a second surface defining a waveguidechannel, wherein the received light total internally reflects along thewaveguide to a periphery of the lens.
 16. The lamp of claim 15, whereinthe first surface includes a multi-faceted optical element and thesecond surface includes an injection surface, wherein said multi-facetedoptical element converges towards the injection surface, wherein saidlens receives light from the light source via the injection surface. 17.The lamp of claim 11, wherein the received light refracts through thefirst surface while total internally reflecting to the periphery of thelens.
 18. A lens comprising: a first surface opposite a second surfacedefining a waveguide channel, wherein the first surface and/or thesecond surface total internally reflect light directed thereto to aperiphery of the lens; an injection surface receiving light from a lightsource; and a multi-faceted optical element opposite the injectionsurface, said multi-faceted optical element converging towards theinjection surface, wherein light received by the injection surface totalinternally reflects off the multi-faceted optical element to theperiphery of the lens.
 19. The lens of claim 18, wherein the secondsurface includes a plurality of converging facets.
 20. The lens of claim18, wherein light refracts out the first surface as it travels along thewaveguide channel to the periphery of the lens.